1. Field of the Invention
The invention relates to a storage medium having an encrypting device according to the preamble of claim 1.
2. Related Art
An example of a known storage medium in the sense of the invention is a flash memory card having an encryption option, having a cryptoprocessor used as an encrypting and a decrypting device, and a symmetrical encryption and decryption key stored in the card for encrypting data. In such a flash memory card a user at a card terminal, e.g. a PC with a flash card reader connected to it or a mobile card terminal such as a mobile telephone with a flash card reader, can optionally select via a menu of the card terminal whether data to be stored in the flash memory card are to be stored in the flash memory card in encrypted form. Unencrypted stored data can be read out of the flash memory card. Encrypted stored data can only be read out of the flash memory card after successful authentication of the user with respect to the flash memory card. If an attempt is made to read out encrypted stored data without authentication, the read-out process is terminated without output of data and possibly with an error message or authentication request being output.
In some applications a holder of a storage medium, who has been requested by an owner of the storage medium to store data on the storage medium, is regarded as potentially untrustworthy by the owner. For example, a monitoring service which stores captured photo or video recordings in a storage medium for monitoring purposes, should have no possibility for reading out the stored photo or video recordings again and misusing them, e.g. to publish them among their associates or on the internet for private purposes. Even if the storage medium has an encryption option, it is possible that the untrustworthy holder simply does not use the same and can therefore read out the stored data arbitrarily after they are stored.
DE 198 03 218 A1 describes a memory card with the features of the preamble of claim 1. Data are either encrypted when being read into the card and decrypted when read out, or read in and out in unencrypted form. US 2008/0071977 A1 shows a card having a fingerprint sensor, which is used to allow access to stored data only to authenticated users.